#100DaysOfCode in Python Transcripts
Chapter: Days 10-12: Testing your code with pytest
Lecture: Testing (simulating) the game end-to-end
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Alright for the final two test methods
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that I actually want to run a whole game from end to end.
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And I'm going to use the same technique as before
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because we're still stuck with this input method
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that requires us to input data which we don't have
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in an automated way of running test with pytest.
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So I'm going to do a patch of the input again
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and I'm going to just simulate a whole game.
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So I'm going to enter 4, 22, 9, 4, and 6.
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They're going to play a win scenario
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and I'm going to give it the input
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which is the requirement of the patch
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but I'm also going to capture the standard out
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as I did before.
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So I make a game.
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And I need to give it a right answer
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to make sense of these numbers.
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So in this scenario win but at the fifth attempt,
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which is 6. So the answer is 6.
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I call the game and assert that the game state
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is underscore win equals true.
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Let's run this.
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Okay. So what it actually did, calling game,
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is it went through all these numbers
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and when it got to the final one, the fifth attempt,
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it asserted answers true, so the win was set to true.
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And again, you can see in the call,
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an actual look that when validate guess returns true,
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which is on the previous test,
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there is an intermediate variable win set to true
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and it also sets the inner, or internal variable win,
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to true. And that's what we are asserting here.
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But what I'm also interested in
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is how the output looks of the program.
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So I can just again do capfd,
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read out err,
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and you can also just call this with zero indexing
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then you don't need the throw-away variable at all.
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And I have a bunch of expected states
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which I'm going to copy in.
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Let's actually assimilate this program.
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So I have these steps I'm just going to
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hard code the answer for a minute, 6.
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So these are the steps.
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So what the test is doing is pretty pretty cool.
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So I'm simulating 4, 22, which is not in range.
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9, 4, 6. So here you see the typical program,
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and that's what we are asserting here
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with these expected values.
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So 4 is too low, number not in range.
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9 is too high, already guessed.
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6 is correct.
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Plus an additional statement of it took you three guesses.
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So let's reset this.
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Let's clean the output from capfd a little,
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with a list comprehension.
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For line in out split by new line.
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Only take lines with one or more characters.
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So ignore blank lines basically.
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And give me the strip lines. So I'm stripping off new lines.
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Alright. And then we can just match it line by line.
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I can use a zip to look over two sequences.
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So you have line and expected in zip output and expected.
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So this will look over expected
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and look over output in parallel.
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So the first value of output
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would match the first value in expected and etc.
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Alright. Look at that. What's my coverage?
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94 percent, very nice.
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So they're only a couple lines missing: 83, 87, 88
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And 87 I'm okay with because this is just a calling code
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if this is called as a script, which we've done before,
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if I call it like this.
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And line 83. Let's see if we can get
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to this scenario as well.
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So this is a lose scenario, where we tried it 5 times
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and still did not assert the answer.
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So let's set up a filled scenario.
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Test, game, lose.
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That's going to follow the same signature as above.
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But I need more stamps.
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So let's do a none, which should not count right away.
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5, 9, 14, 11, 12, doesn't really matter
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because what I need to do now
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is to give it an answer that's just totally different.
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So let's make a game.
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And the game answer is 13. So it's not in all my guesses.
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But this also test that none doesn't count
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towards my guesses. So I can actually do 6 inputs
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and this would be the fifth guess.
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So I'm actually getting here in the first place.
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Play the game.
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I won't win this game.
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And it should pass, right,
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but the coverage should still be the same
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because I'm not hitting that line yet.
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I do. Yeah, I did.
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So just to recap, this was line 83,
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which corresponds to this line.
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And what happened here, I played,
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actually what I forgot is that this plays the whole game.
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When I launch game, it goes through all these outputs.
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And having guessed 5 times,
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and not asserting this answer, I did get to the L's block.
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I can actually show that. If I turn on non-capture mode.
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See? It just prints the whole thing.
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5's too low, 9 is too low, then I guessed 5 times.
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Answer is 13. So I made it to this actual print statement.
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And that was the final thing
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to actually increase the coverage.
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If you take main out, we have a 100% coverage
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of our tests. You still need to have a critical eye
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to your code and your tests
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because one thing is to test it,
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but, for example, I can get a 100%
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on this earlier validation of the guesses,
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sorry, this one,
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but here I made sure that I'm going
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into all the different kind of value errors.
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Actually let's do an experiment.
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If I'm not doing the not-a-number test,
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would my coverage go down?
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Wow, look at that, how cool.
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So I took a test out
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and now it's complaining that 35 and 36 are missing.
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And 35 36 is they should be a number,
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and that's the thing we just deleted.
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So I had a string here,
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and that not-a-number should raise an exception.
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And coverage spotted that. So that's very cool,
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that you can just pinpoint exactly which code
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is not being tested versus which code it is.
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But again, you still need to have a critical eye
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of what you're testing.
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Because one thing is to have all your lines, some were called,
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but the other thing is how you call them.
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What are you testing? Are you testing all the edge cases?
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So testing is an art in itself.
